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Engineered Material Arresting System (EMAS)

The Federal Aviation Administration (FAA) requires that commercial service airports, regulated under Part 139 safety rules and federally obligated, have a standard Runway Safety Area (RSA) where possible. The RSA is typically 500 feet wide and extends 1,000 feet beyond each end of the runway. The FAA has this requirement in the event that an aircraft overruns, undershoots, or veers off the side of the runway. Many airports were built before the 1,000-foot RSA length was adopted some 20 years ago, and it is not practicable to achieve the full standard RSA. This is due to obstacles such as bodies of water, highways, railroads, populated areas or severe drop-off of terrain.

The FAA began conducting research in the 1990s to determine how to ensure maximum safety at airports where the full RSA cannot be obtained. Working in concert with the University of Dayton, the Port Authority of New York and New Jersey, and the Engineered Arresting Systems Corporation (ESCO) of Logan Township, N.J., a new technology emerged to safely arrest overrunning aircraft. The Engineered Material Arresting System (EMAS) uses crushable concrete placed at the end of a runway to stop an aircraft that overruns the runway. The tires of the aircraft sink into the lightweight concrete, and the aircraft is decelerated as it rolls through the material.

Benefits of the EMAS Technology

The EMAS technology improves safety benefits in cases where land is not available or where it is not possible to have the standard 1,000-foot overrun. A standard EMAS installation extends 600 feet from the end of the runway. An EMAS arrestor bed can be installed to slow or stop an aircraft that overruns the runway, even if less than 600 feet of land is available.

Current FAA Initiatives

In 2005 the Office of Airports prepared an RSA improvement plan for runways at approximately 575 commercial airports. This plan allows the agency to track progress and to direct federal funds for making all practicable improvements, including the use of EMAS technology. Of the approximately 1,000 RSAs at these airports, an estimated 65 percent have been improved to full standards, and an estimated 87 percent have been improved to the extent practicable, not including the relocation of FAA-owned navigational equipment.

Presently, the EMAS system developed by ESCO using crushable concrete is the only system that meets the FAA standard. The FAA has conducted research through the Airport Cooperative Research Program (ACRP) that examined a number of alternatives to the existing approved system. ACRP Report 29, Developing Improved Civil Aircraft Arresting Systems, is available at the Transportation Research Board.

Many of the EMAS beds installed prior to 2006 need periodic repainting to maintain the integrity and functionality of the bed. The EMAS manufacturer has developed improved plastic seal coating for EMAS beds, which should eliminate the need for the periodic repainting.

EMAS Arrestments

To date, there have been eight incidents where EMAS has safely stopped overrunning aircraft with a total of 235 crew and passengers aboard those flights.

EMAS Installations

Currently, EMAS is installed at 63 runway ends at 42 airports in the United States, with plans to install three EMAS systems at three additional U.S. airports.

For the full listing of EMAS arrestments and installations, visit

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